Question

The self inductance of a long solenoid cannot be increased by

• A. Increasing its area of cross-section
• B. Increasing its length
• C. Changing the medium with greater permeability
• D. Increasing the number of turns in it
• E. Increasing the current through it

Answer 1

The correct option is E Increasing the current through it

The self-inductance of a long solenoid
$L=\frac{\mu N^{2}A}{l}$

From the above expression, it is clear that the self-inductance of a long solenoid does not depend upon the current flowing through it.

i.e., the self-inductance of a long solenoid cannot be increased by increasing the current through it.